The invention relates to a fluid interlinked brake for single-track vehicles which has two brake systems associated with respective front and rear wheels, each comprising at least one brake unit and two independent actuators, one connected to each of the brake systems; and to a single-track vehicle having such a brake.
The brakes of single-track road vehicles must have two systems available, each of which acts to ensure the required security against failure even when the other fails. As a rule, at least one manually operated front wheel brake and a foot-operated rear wheel brake independent of the front wheel brake are provided. Because of the ratio of wheel base to height of center of gravity in conventional single-track vehicles, up to 100% of the total weight shifts onto the front wheel in a severe brake application. When the front wheel is locked by braking, the vehicle immediately loses its dynamic stability and unless the locking ceases rapidly the vehicle falls over. Consequently, brake applications near the maximum coefficient of friction must not overbrake the front wheel before the rear wheel. Optimal graduation of the braking force by the driver by means of the hand brake and foot brake of conventional single-track vehicles is very difficult and at times is virtually impossible because of the total weight shift and the resulting alteration in braking force distribution for minimal braking distance and, more particularly in the light of variable coefficients of friction of the road, for example, because of differences in road surfaces, wetness, dirt, oil, frost and so on. A choice must be made between overlong braking distances or the risk of falling. Because of graduation problems it has so far proved impossible to use braking force amplifiers.
Various interlinked brake devices are known. Because of the forward displacement of vehicle weight which occurs in braking, many vehicles have one or two front wheel brakes and a single rear wheel brake. In a partially interlinked brake device known since 1925 a front wheel brake and a rear wheel brake can be operated mechanically by the brake pedal and failure protection is provided by manual operation of the second front wheel brake. Corresponding hydraulic, partially interlinked devices have been known since about 1970 which are adapted to individual vehicle characteristics to some extent by differences in brake disc diameter and/or brake caliper transmission ratios.